Ferro-electric stacked gate oxide heterojunction electro-statically doped source/drain double-gate tunnel field effect transistors: A superior structure

The effect of ferro-electric (Fe) gate oxide on heterojunction and band-gap engineering based electro-statically doped source/drain (EDSD) double-gate Tunnel Field Effect Transistors (DG-TFETs), has been studied through 2-D TCAD device simulation. The combined effects of ferroelectric gate stack oxide and the hetero-junction, with low band gap material at source side and high band gap material in rest of the device helps to improve the performance of TFETs. The comparison of various low band gap source region materials shows that Hetrojunction Si-Ge EDSD Fe-DGTFET gives highest on-off current ratio of approx. 1013 and approximately 3 mV/dec subthreshold swing. Further, comparison of different hetro-structures is done on the basis of analog characteristics and shows that Hetrojunction Si-Ge EDSD Fe-DGTFET gives lowest intrinsic delay of 1.576×10−11 s, thus improving device speed. Moreover, some other analog parameters like gate to source capacitance, gate to drain capacitance, total capacitance, and transconductance and unity gain frequency are also studied to give an idea about improvement in device characteristics